This invention relates generally to communications networks and more particularly to providing reliable internetworking communications.
Communication networks are known to include a plurality of switches that are interoperably coupled to support communications between users coupled to ports of the communication network. The users may be end-users such as personal computers, telephones, videophones, etc., or may be servers, routers, private branch exchange (PBX), etc. Such users communicate in various forms such as voice, data, or a combination thereof via communication paths supported by the communication networks. The communication paths may be established using dedicated links or allocating links upon receipt of communication requests.
Many communication networks include a network service controller such as the network service controller 46020 manufactured and distributed by Newbridge Networks Corporation. The network service controller (NSC) manages the communication network by establishing the dedicated communication links, performing diagnostics on switches and/or links within the network, and configuring the switches and/or links.
To expand coverage area of a communication network, several communication networks may be linked together. To support such linking, each communication network includes a plurality of network-to-network interfaces (NNI) and a plurality of user-to-network interface (UNI). As the names imply, the UNI allows a user to interface with the network(s) while the NNI provides coupling, on a one-to-one or a one-to-many basis, between networks. To further support the linking of multiple communication networks, a Multi-Network Service Controller (MNSC), such as the 48020 manufactured and distributed by Newbridge Networks Corporation, is included. The MNSC manages the resources of the outer edges of the network (i.e., the UNIs and NNIs). As part of the MNSC""s management function, it establishes communication links between UNIs based on user request to form a communication path, which may be comprised of dedicated communication links (i.e., links that are permanently assigned) or allocated communication links (i.e., links that are assigned when needed). In either case, the MNSC manages the internetworking links (i.e., the links coupling the networks) and requests of the NSC to establish intranetworking links (i.e., the links within a network). At this point, the NSC establishes the intranetworking links to complete the communication path between the endpoint users.
An issue arises when an NSC is unable to establish an intranetworking communication link, or when an intranetworking link (i.e., resource) fails. Such failure may occur due to all resources being used, not having sufficient bandwidth to support the current request, the intranetworking communication resources are broken, etc. When an intranetworking resource fails, the NNSC is unaware of the type of failure, thus, to the MNSC, the communication path has failed and has no way to correct the failure. Only the NSC of the network containing the failed intranetworking resource(s) is aware of the type of failure and is the only entity capable of fixing the failure. As such, the NSC attempts to reestablish reliable intranetworking paths while the MNSC remains idle for this communication. Depending on the type of failure, it may take several hours to repair the intranetworking resource(s).
Therefore, a need exists for a method and apparatus for a Multi-Network Service Controller to provide reliable internetworking services when an intranetworking resource fails.